Electronic parts mounting apparatus

ABSTRACT

An electronic parts mounting apparatus for divisionally recognizing an electronic part ( 2 ) even when the apparatus is arranged in such that the relative positional relation between a recognition camera ( 4 ) and a nozzle ( 1 ) cannot be varied. The electronic part ( 2 ) is vacuum-clamped by a nozzle ( 1 ), the posture of the nozzle ( 1 ) or the posture of the electronic part ( 2 ) is changed a plurality of times by a rotary driving member ( 3 ), and a part of the electronic part ( 2 ) imaged by the recognition camera ( 4 ) every time the posture of the electronic part ( 2 ) is changed, whereby the part is recognized. Thus, the recognition of the contour of the electronic part ( 2 ) becomes possible, and the electronic part can be mounted accurately on a circuit board by making a positional correction on the basis of the amount of deviation obtained.

TECHNICAL FIELD

The present invention relates to an electronic parts mounting apparatusfor mounting electronic parts on a circuit board.

BACKGROUND ART

Recently, as electronic circuit boards become more and more highly denseand functional, and integrated electronic parts become larger and largerin size, high accuracy is demanded for an electronic parts mountingapparatus. Thus, it becomes necessary to mount the electronic parts onthe electronic circuit board by accurately recognizing them andcorrecting their positions. In this case, since a visual field size isselected for a recognition camera from required mounting accuracy,divisional recognition means is employed to recognize an electronic partlarger than the visual field size.

Now, explanation is given on an example of operation for recognizing anelectronic part in an electronic parts mounting apparatus with referenceto the drawings.

FIG. 9(a) shows a relationship between a visual field 10 of arecognition camera, an electronic part 2, and a nozzle 1 for holding theelectronic part 2. When the electronic part 2 is smaller than the visualfield of camera 10, as shown, the electronic part 2 can be recognized byaligning the position of the nozzle 1 at the center of visual field.

FIG. 9(b) shows a case where the electronic part 2 is larger than thevisual field of camera 10. In this case, to recognize the electronicpart 2, it is necessary to perform divisional recognition by varying therelative positional relationship between the nozzle 1 and the visualfield of camera 10 as indicated by arrow.

As described, it is necessary to perform the divisional recognition torecognize the electronic part 2 larger than the visual field of camera10. However, to vary the relative positional relationship between thenozzle 1 and the visual field of camera 10, it should be arranged thatthe nozzle 1 or the camera (visual field 10) can freely move on a planeopposite to the electronic part 2. Thus, there is a problem that thedivisional recognition of the electronic part cannot be performed on anelectronic parts mounting apparatus on which the relative positionalrelationship between the nozzle 1 and the camera cannot be varied.

In addition, the method performing divisional recognition by varying therelative positional relationship between the nozzle 1 and the visualfield of camera 10 has a problem that it takes more time than the methodperforming recognition with a single visual field because the formercaptures images a plurality of times.

DISCLOSURE OF THE INVENTION

The present invention is intended to provide an electronic partsmounting apparatus which enables it to perform divisional recognition ofan electronic part even when a relative positional relationship betweena nozzle and a camera is not varied, and which can use the divisionalrecognition and single visual field recognition in combination, so thatrecognition is performed in a single visual field for an electronic partwhich can be recognized in a single visual field, enabling the time ofrecognition to be shortened.

To attain the above object, the electronic parts mounting apparatus ofthe present invention comprises a nozzle for holding an electronic part,a rotary driving member for rotating and driving the nozzle in a desiredangle, a recognition camera for imaging the electronic part held by thenozzle, and part recognition means for changing a plurality of times theposture of the electronic part held by the nozzle with the rotarydriving member when the center of the visual field of the recognitioncamera is positioned at a position different from the center of rotationof the nozzle, and recognizing the electronic part from partialrecognition images obtained from the recognition camera every time theposture is changed.

According to the present invention, it is possible to obtain anelectronic parts mounting apparatus enabling it to perform divisionalrecognition of an electronic part even when the relative positionalrelationship between the nozzle and the camera is not varied.

An electronic parts mounting apparatus according to a first aspect ofthe present invention comprises a nozzle for holding an electronic part,a rotary driving member for rotating and driving the nozzle in a desiredangle, a recognition camera for imaging the electronic part held by thenozzle, and part recognition means for changing a plurality of times theposture of the electronic part held by the nozzle with the rotarydriving member when the center of the visual field of the recognitioncamera is positioned at a position different from the center of rotationof the nozzle, and recognizing the electronic part from partialrecognition images obtained from the recognition camera every time theposture is changed.

Thus, there is an advantage that even an electronic parts mountingapparatus arranged not to be capable of varying the positionalrelationship between the recognition camera and the electronic part tobe recognized can recognize the contour of the electronic part bychanging the posture of the electronic part a plurality of times withthe rotary driving member, and capturing a partial image every time theposture is changed to recognize the contour of the electronic part.

An electronic parts mounting apparatus according to a second aspect ofthe present invention comprises a nozzle for holding an electronic part,a rotary driving member for rotating and driving the nozzle in a desiredangle, a first recognition camera positioned with the center of itsvisual field at a position coincident with the center of rotation of thenozzle, and for imaging the electronic part held by the nozzle, a secondrecognition camera positioned with the center of its visual field at aposition different from the center of rotation of the nozzle, and forimaging the electronic part held by the nozzle, and part recognitionmeans, when recognizing an electronic part smaller than the visual fieldsize of the camera, for batch recognizing the electronic part from arecognized image of the electronic part obtained from the firstrecognition camera, and, when recognizing an electronic part larger thanthe visual field size of the camera, for changing a plurality of timesthe posture of the electronic part held by the nozzle with the rotarydriving member, and recognizing the electronic part from partialrecognized images obtained from the second camera every time the postureis changed.

As the first recognition camera the center of visual field of whichaligns the center of rotation of the nozzle is used for a smallelectronic parts which can be recognized with a single visual field, andthe second recognition camera the center of visual field of whichdiffers from the center of rotation of the nozzle is used for a largeelectronic part, there is provided an advantage that batch recognitionand divisional recognition can be used in combination for recognizing anelectronic part without varying the relative positional relationshipbetween the nozzle and the first and second recognition cameras, so thattime for recognition can be shortened.

An electronic parts mounting apparatus according to a third aspect ofthe present invention a nozzle for holding an electronic part, a rotarydriving member for rotating and driving the nozzle in a desired angle, arecognition camera for imaging the electronic part held by the nozzle, adriving mechanism for varying the relative positional relationshipbetween the center of visual field of the recognition camera and thecenter of rotation of the nozzle, and part recognition means, whenrecognizing an electronic part smaller than the visual field size ofcamera, for batch recognizing the electronic part from a recognizedimage of the electronic part obtained from the recognition camera byaligning the center of visual field of the recognition camera with thecenter of rotation of the nozzle with the driving mechanism, and, whenrecognizing an electronic part larger than the visual field size of thecamera, for changing a plurality of times the posture of the electronicpart held by the nozzle with the rotary driving member, and recognizingthe electronic part from partial recognized images of the electronicpart obtained from the camera every time the posture is changed.

There is provided an advantage that batch recognition and divisionalrecognition can be used in combination for recognizing an electronicpart by varying the relative positional relationship between therecognition camera and the electronic part with the driving mechanism,so that the time for recognition can be shortened.

An electronic parts mounting apparatus according to a fourth aspect ofthe present invention is a one according to the third aspect of thepresent invention, wherein, when either one of the center of visualfield of the recognition camera and the center of rotation of the nozzleis determined to be a reference for the driving mechanism, its drivingdirection is limited to one fixed direction.

This arrangements provide an advantage that the driving mechanism can besimplified.

An electronic parts mounting apparatus according to a fifth aspect ofthe present invention is one according to the third aspect of thepresent invention, further comprising calculation means for calculatinga location for movement of the recognition camera from previouslyregistered data on the center of rotation of the nozzle, the drivingmechanism moving the recognition camera to the location for movementcalculated by the calculation means.

There is provided an advantage that divisional recognition can beperformed even when the center of rotation data of the nozzle is varied.

An electronic parts mounting apparatus according to a sixth aspect ofthe present invention is one according to the third aspect of thepresent invention, further comprising calculation means for calculatinga location for movement of the recognition camera from previouslyregistered sizes of electronic parts, the driving mechanism moving therecognition camera to the location for movement calculated by thecalculation means.

There is provided an advantage that divisional recognition can beperformed even when the outer size of an electronic part is varied.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 1 of thepresent invention;

FIGS. 2(a)-(d) are diagrams for illustrating operation of the partrecognition mechanism of the above electronic parts mounting apparatus;

FIG. 3 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 2 of thepresent invention;

FIG. 4 is a diagram for illustrating operation of the part recognitionmechanism of the above electronic parts mounting apparatus;

FIG. 5 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 3 of thepresent invention;

FIGS. 6(a)-(b) are diagrams for illustrating operation of the partrecognition mechanism of the above electronic parts mounting apparatus;

FIG. 7 is a diagram for illustrating operation of the part recognitionmechanism of the above electronic parts mounting apparatus;

FIG. 8 is a diagram for illustrating operation of the part recognitionmechanism of the above electronic parts mounting apparatus; and

FIGS. 9(a)-(b) are diagrams for illustrating operation of the partrecognition mechanism of the above electronic parts mounting apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1

FIG. 1 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 1 of thepresent invention.

Referring to FIG. 1, there is shown a nozzle 1 for sucking and holdingan electronic part 2, the nozzle 1 being rotatable in any desired angleby a rotary driving member 3. In the figure, the rotary driving member 3comprises a pulse motor 11, a first gear 12 coupled to the rotatingshaft of the motor 11, and a second gear 13 rotating around the centerof rotation 5 of the nozzle 1 and meshing the first gear. An AC servomotor may be used in place of the pulse motor 11.

Also in FIG. 1, there is shown a mirror assembly 7 constituted byoppositely arranging two mirrors 14 and 15, the mirror 14 being disposedto face the bottom of the electronic part 2, so that an image of theelectronic part 2 can be viewed from above with the other mirror 15. Arecognition camera 4 is disposed over the other mirror 15 by offsettingthe center of rotation 5 of the nozzle 1 from the center of visual field6, as shown in FIG. 2.

A signal of an image imaged by the recognition camera 4 is input into apart recognition unit 8. The part recognition unit 8 comprises an imageprocessor 21 for recognizing the image of the electronic part 2 with theinput image signal, an image synthesizer 22 for synthesizing a pluralityof partial images recognized by the image processor 21, a motor driver23 for rotationally changing the posture of the nozzle 1, or the postureof the electronic part 2 by outputting a rotationally driving signal tothe pulse motor 11 in the rotary driving member 3, a storage 24 forstoring data of the partial images or the like, and a controller 25 forgenerally controlling the image processor 21, the image synthesizer 22,the motor driver 23 and the storage 24 in response to a part recognitioninstruction signal from a controller (not shown) of the electronic partsmounting apparatus.

The operation of the part recognition mechanism with the abovearrangement is described with reference to FIGS. 2(a)-(d).

Step-1

When a part recognition instruction signal is input, the controller 25drives and causes the image processor 21 to recognize partial images ofthe electronic part 2 with the image signal imaged by the recognitioncamera 4, and then stores partial image data in the storage 24.

Step-2

Then, the controller 25 drives the rotary drive section 3 to rotate theposture of the nozzle 1, or the posture of the electronic part 2 by 90°,for example, as shown in FIG. 2(b).

Steps-1 and -2 are repeated FIGS. 2(c) and (d).

Step-3

When the posture or nozzle 1 or electronic part 2 is changed three timesaccording to Step-2, and recognition of the partial images of theelectronic part 2 according to Step-1 completes four times, the partialimage data stored in the storage 24 is output to the image synthesizer22, whereby an image of the entire electronic part 2 is recognized.

Step-4

Amount of offset is determined and output between the center of therecognized electronic part 2 and the center of rotation 5 of the nozzle1.

Thus, the contour of the electronic part 2 can be recognized by changingthe posture of the nozzle 1 or the electronic part 2 a plurality oftimes with the rotary driving member 3, capturing partial images everytime the posture is changed, and performing partial recognition. Then,the electronic part 2 can be precisely and accurately mounted on acircuit board by correcting the position when mounting the electronicpart based on amount of deviation obtained.

Embodiment 2

FIG. 3 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 2 of thepresent invention. Components similar to those of the above embodiment 1are designated by the same reference numerals, and omitted for theirdescription.

A mirror assembly 7′ is provided with a half-mirror 16 in addition totwo mirrors 14 and 15. This arrangement means that an image of theelectronic part 2 can be viewed from the above also by the half-mirror16. A second recognition camera 4B is disposed at a position over thehalf-mirror 16 of the mirror assembly 7′, with its center of visualfield being offset from that of a first recognition camera 4A, as shownin FIG. 4. The center of visual field 6A of the recognition camera 4A isoffset from the center of rotation 5 of the nozzle, while the center ofvisual field 6B of the recognition camera 4B aligns the center ofrotation 5 of the nozzle.

With the above arrangement, when the controller 25 of the partrecognition unit 8 recognizes an electronic part 2 smaller than thevisual field of the recognition camera under a part recognitioninstruction signal, it inputs an image signal from the recognitioncamera 4B into the image processor 21, thereby performing batchrecognition, and when it recognizes an electronic part larger than thevisual field of the recognition camera under a part recognitioninstruction signal, it inputs an image signal from the recognitioncamera 4A into the image processor 21, whereby the posture of the nozzle1 or the electronic part 2 is rotationally changed by the rotary drivingmember 3 as in the above embodiment 1 to capture images a plurality oftimes for divisional recognition of the electronic part 2.

Thus, single-visual field recognition and multi-visual field divisionalrecognition can be performed without changing the relative positionalrelationship between the nozzle 1 and the recognition cameras 4A, 4B.Then, the camera 4B in which the center of its visual field aligns thecenter of rotation of the nozzle is used for a small electronic part 2which can be recognized with a single visual field, while therecognition camera 4A in which the center of its visual field is offsetfrom the center of rotation of the nozzle is used for a large electronicpart, so that the time of recognition can be shortened.

Embodiment 3

FIG. 5 is an arrangement of a part recognition mechanism of anelectronic parts mounting apparatus according to embodiment 3 of thepresent invention. Components similar to those of the above embodiment 1are designated by the same reference numerals, and omitted for theirdescription.

Referring to FIG. 5, there is shown an XY table (driving mechanism) 9which makes the mirror assembly 7 and the recognition camera 4 movablerelative to the electronic part 2. The relative positional relationshipbetween the recognition camera 4 and the nozzle 1 or the electronic part2 can be varied by driving the XY table 9. The XY table 9 is driven byan actuator such as an AC servo motor. The nozzle 1 and the rotarydriving member 3 may be contrarily made movable by the XY table 9.

Furthermore, in FIG. 5, there is shown a storage 31 previously storingposition data of the center of rotation of the nozzle 1 and electronicpart sizes, and a controller 32 for the XY table 9 for calculating thepositional relationship between the center of rotation 5 of the nozzleand the center of visual field 6 of the camera using the position dataof the center of rotation of the nozzle and the electronic part sizesstored in the storage to drive the XY table 9.

With the above arrangement, when an electronic part 2 smaller than thevisual field of the recognition camera is recognized by using thecontroller 32 for the XY table 9, the XY table 9 is driven in such that,as shown in FIG. 6(a), the center of recognition visual field 6 alignsthe center of rotation 5 of the nozzle. When an electronic part 2 largerthan the visual field of the recognition camera is recognized, the XYtable 9 is driven such that, as shown in FIG. 6(b), the center of visualfield 6 of the camera is offset from the center of rotation of thenozzle, so that a part of the electronic part 2 enters in the visualfield of the camera. The part recognition method with the partrecognition unit 8 is similar to the above embodiment. Then, when anelectronic part 2 smaller than the visual field of the recognitioncamera is recognized, it is batch recognized, while, when an electronicpart larger than the visual field of the recognition camera, partialimages are captured a plurality of times for divisional recognition ofthe electronic part 2 by changing the posture of the nozzle 1 or theelectronic part 2 by the rotary driving member 3.

In this way, batch recognition and divisional recognition can besimultaneously employed by varying the relative positional relationshipbetween the recognition camera 4 and the nozzle 1 or the electronic part2 with the XY table 9.

In this case, since the size of visual field of the camera should beeffectively used, in performing the divisional recognition, the positionof the nozzle relative to the visual field of recognition is on astraight line extending from the center of visual field 6 toward acorner of the visual field as shown in FIG. 6(b). To this end, it may beone direction to vary the center of rotation 5 of the nozzle and thecenter of visual field 6 of the camera. In this case, the XY table 9 canbe of a simple structure, so that cost can be reduced.

Description is given on calculation of the positional relationshipbetween the center position of rotation 5 of the nozzle and the centerof visual field 6 of the camera, and driving of the XY table 9 by thecontroller 32 for the XY table 9.

FIG. 7 shows an operation when the center position of rotation 5 of thenozzle is varied.

When the position of nozzle 5 is varied by (ΔX, ΔY), the electronic part2 cannot be contained in the visual field of camera and divisionalrecognition is impossible. In this case, the divisional recognition canbe performed for the electronic part 2 by varying the positionalrelationship between the center of rotation 5 of the nozzle and thecenter of visual field 6 of the camera by (ΔX, ΔY) with the XY table 9.

Then, FIG. 8 shows an operation when the size of electronic part isvaried.

When it is assumed that the size of visual field of recognition camerais X, the outer size of electronic part is L, and margin fordisplacement of the electronic part or the like is ΔL, the relativeposition ΔX between the center of nozzle 5 and the center of visualfield 6 of the camera is sufficient to be in a positional relationshipcalculated by:

ΔX=(L+2ΔL−X)/2

Thus, the divisional recognition can be performed even when the size ofelectronic part is varied.

What is claimed is:
 1. An electronic parts mounting apparatus comprising: a nozzle for holding an electronic part, a rotary driving member for rotating and driving said nozzle in a desired angle, a recognition camera for imaging the electronic part held by said nozzle, and part recognition means for changing a plurality of times the posture of the electronic part held by said nozzle with said rotary driving member when the center of the visual field of said recognition camera is positioned at a position different from the center of rotation of said nozzle, and recognizing the electronic part from partial recognition images obtained from said recognition camera every time the posture is changed.
 2. An electronic parts mounting apparatus comprising: a nozzle for holding an electronic part, a rotary driving member for rotating and driving said nozzle in a desired angle, a first recognition camera positioned with the center of its visual field at a position coincident with the center of rotation of said nozzle, and for imaging the electronic part held by the nozzle, a second recognition camera positioned with the center of its visual field at a position different from the center of rotation of said nozzle, and for imaging the electronic part held by the nozzle, and part recognition means, when recognizing an electronic part smaller than the visual field size of camera, for batch recognizing the electronic part from a recognized image of said electronic part obtained from said first recognition camera, and, when recognizing an electronic part larger than the visual field size of camera, for changing a plurality of times the posture of the electronic part held by said nozzle with said rotary driving member, and recognizing the electronic part from partial recognized images obtained from said second camera every time the posture is changed.
 3. An electronic parts mounting apparatus comprising: a nozzle for holding an electronic part, a rotary driving member for rotating and driving said nozzle in a desired angle, a recognition camera for imaging the electronic part held by said nozzle, a driving mechanism for varying the relative positional relationship between the center of visual field of said recognition camera and the center of rotation of said nozzle, and part recognition means, when recognizing an electronic part smaller than the visual field size of camera, for batch recognizing the electronic part from a recognized image of said electronic part obtained from said recognition camera by aligning the center of visual field of said recognition camera with the center of rotation of said nozzle with said driving mechanism, and, when recognizing an electronic part larger than the visual field size of camera, for changing a plurality of times the posture of said electronic part held by said nozzle with said rotary driving member, and recognizing the electronic part from partial recognized images of said electronic part obtained from said camera every time the posture is changed.
 4. The electronic parts mounting apparatus as set forth in claim 3, wherein, when either one of the center of visual field of the recognition camera and the center of rotation of the nozzle is determined to be a reference for the driving mechanism, its driving direction is limited to one fixed direction.
 5. The electronic parts mounting apparatus as set forth in claim 3, wherein calculation means is added for calculating a location for movement of the recognition camera from previously registered data on the center of rotation of the nozzle, and the driving mechanism moves the recognition camera to the location for movement calculated by said calculation means.
 6. The electronic parts mounting apparatus as set forth in claim 3, wherein calculation means is added for calculating a location for movement of the recognition camera from previously registered sizes of electronic parts, and the driving mechanism moves the recognition camera to the location for movement calculated by said calculation means.
 7. An electronic parts mounting method using an electronic parts recognition mechanism rotating an electronic part held by a nozzle, capturing an image of the electronic part by a recognition camera fixed at a position, and collecting a plurality of thus captured images into a composite image, said method comprising the steps of: (a) capturing an image of the electronic part by the recognition camera; (b) rotating the nozzle holding the electronic part for a certain amount and thereafter capturing a posture image of the electronic part; (c) repeating step b) once or a plurality of times; and (d) recognizing the contour of the entire electronic part by processing each of the captured images into a composite image.
 8. An electronic parts mounting method as set forth in claim 7 wherein during step (d) of recognizing the contour of the entire electronic part, the amount of offset of the center of the electronic part from the center of the image is detected, thereby correcting the mounting of the electronic part.
 9. An electronic parts mounting method using an electronic parts recognition mechanism rotating an electronic part held by a nozzle, capturing an image of the electronic part by a recognition camera selected from two recognition cameras fixed at different positions apart from each other by a certain distance, and collecting a plurality of thus captured images into a composite picture, said method comprising the steps of: comparing the size of the electronic part and the size of visual field of the camera; when the size of the electronic part is smaller than that of the visual field of the camera, switching on the first recognition camera with which the center of visual field of the camera and the center of rotation of the nozzle correspond to each other, thereby performing a batch recognition of the electronic part; and when the size of the electronic part is larger than that of the visual field of the camera, switching on the second recognition camera with which the center of visual field of the camera and the center of rotation of the nozzle differ from each other, and each time when the nozzle holding the part is rotated for a certain amount, dividing the image of the electronic part and capturing the divided images into a composite picture, thereby recognizing the contour of the entire electronic part.
 10. An electronic parts mounting method using an electronic parts recognition mechanism rotating an electronic part held by a nozzle, capturing an image of the electronic part by a recognition camera, collecting a plurality of thus captured images into a composite image, and a drive mechanism for varying a relative positional relation between the center of visual field of the recognition camera and the center of rotation of said nozzle, said method comprising the steps of: comparing the size of the electronic part and the size of visual field of the camera; when the size of the electronic part is smaller than that of the visual field of the camera, performing a batch recognition by actuating the drive mechanism such that the center of visual field of the camera and the center of rotation of the nozzle correspond to each other; and when the size of the electronic part is larger than that of the visual field of the camera, dividing the image of the electronic part and capturing the divided images into a composite image each time the nozzle holding the part is rotated for a certain amount, while the drive mechanism is being actuated such that the center of visual field of the recognition camera and the center of rotation of the nozzle differ from each other by a certain distance, thereby recognizing the contour of the entire electronic part. 